Annealing effects and optical properties of Si: SiO2 films prepared by radio frequency sputter

We fabricated Si: SiO2 films and assessed its optical characteristics using photoluminescence spectroscopy. The Si: SiO2 films were deposited by sputtering Si tablets (15 mm square) onto a SiO2 target (108 mm diameter). Using excitation by a He-Cd laser, photoluminescence was emitted from the films. The bluish color emission was seen by the naked eye at room temperature. Photoluminescence spectra, that were measured from 400 nm to 1100 nm, were wide and continuous with some peaks. After annealing, that emission of photoluminescence decreased and its color changed to red.